The present invention relates to a display unit lifter, and more particularly relates to improvements in construction and function of a lifter suited, in particular, for use with a liquid crystal (LC) display unit.
Various lifters have been proposed for automatic lifting of display units. Operations of these automatic lifters are commonly based on use of a pinion-rack combination. More specifically, a table bearing a display unit is associated with at least one pinion driven for rotation by a drive motor carried by the table. The pinion is kept in meshing engagement with a vertical rack. As the pinion rotates on the rack, the table with the display unit moves upwards and downward depending on the direction of pinion rotation.
In the construction of one typical example of the conventional lifter, a horizontal table bearing a display unit and its accessories is encased within a housing for vertical movement. A drive motor attached underneath the table has a pair of opposite output shafts. The output shafts extend horizontally across the interior of the housing and are provided with pinions fixed at their distal ends. At positions corresponding the pinions, a pair of racks are fixed vertically to one inner side wall of the housing in meshing engagement with the associated pinions. One or more telescopic damper supports are interposed between the lower face of the table and the interior bottom of the housing. As the pinions are driven for rotation, the table with the display unit moves vertically in the housing while the damper supports cushion such vertical movement of the table with the display unit.
The conventional lifter of the above-described construction is well suited for use with a cathode ray tube (CRT) display unit which is rather large and heavy in construction. The table is required to have a dimension and strength sufficient for bearing such a large and heavy CRT display unit. Use of the pinion-rack combinations necessitates an increased dimension of the housing, namely the entire system. As well known in the field of art, LC display units are generally lighter and smaller in construction than CRT display units. As a consequence, the conventional lifter of the above-described construction is rather unsuited for use with a contemporary LC display unit.
When any foreign materials accidentally fall on the pinion or on the rack, the pinion cannot rotate smoothly on the associated rack. Subsequent forced rotation of the pinion unavoidably causes breakage and/or malfunction of the related parts such as the drive motor.
In addition, due to poor luminous emanation on the screen of an LC display unit, images appearing on the screen of an LC display unit are not so clear as those on a CRT display. In order to compensate this disadvantage, it is necessary to correctly position the screen of an LC display unit in relation to the user's eyes. Stated otherwise, the screen angle of a LC display unit should be adjusted to tile optimum one in relation to the user's eyes. Since it is rather cumbersome to manually optimize the screen angle at every use of an LC display unit, it is strongly wanted by general user to provide a new system which enables automatic optimization of the screen angle. Despite such a demand, the above-described construction of the conventional lifter has no function of the automatic angular optimization.